About ToolKoala — Browser-Based File Tools That Never Upload

Milo the koala
Milo 🐨
tool obsessive · privacy paranoid · founder of one

Hi, I'm Milo 🐨 — the human behind ToolKoala. I make these tools nights and weekends because I needed them and got tired of every other "free" online tool asking for my email, my files, and my patience.

ToolKoala is a collection of 100+ file-processing tools that run entirely in your browser. No upload, no signup, no watermark. We made it because the existing "online converters" world is broken in a specific way, and we wanted something that wasn't.

The story

In 2024, I needed to compress a video of my daughter's birthday before emailing it to my parents. Gmail's 25 MB attachment limit blocked it. I searched "compress video online," clicked the first result, and started uploading the file. Halfway through the upload, I read the site's privacy policy. The site reserved the right to "retain uploaded files for system improvement purposes." I cancelled the upload.

Modern browsers can run real software now — Photoshop-grade image processing, FFmpeg video encoding, full PDF rendering, OCR, even neural networks for background removal. The compiled binaries weigh 10-30 MB and load on demand. There is no technical reason these jobs need to happen on someone else's server. The reason most do is that server-side is easier to monetize: gate features behind subscriptions, harvest usage analytics, train models on user uploads.

I wanted a tool that took the harder engineering path and gave back the obvious user benefit: your files don't go anywhere. Not because we promise — because you can verify. Open Chrome DevTools, click the Network tab, drop a file into any tool on this site. You'll see the tool's code load (cached after the first time), but you won't see your file go out.

What's here today

As of mid-2026, ToolKoala has:

  • 100+ tools across image editing, PDF workflows, video/audio processing, text manipulation, developer utilities, and document conversion.
  • 8 languages (English, Simplified Chinese, Traditional Chinese, Japanese, Spanish, Korean, Portuguese, German).
  • Zero file uploads for every tool — verifiable in your browser's DevTools.
  • No accounts, no paywalls, no watermarks. Every feature is free for unlimited use.

Highlights include AI-powered background removal (U2-Net via WebGPU), browser-native video and audio compression (FFmpeg.wasm), OCR for 12+ languages (Tesseract.js), and a full PDF suite built on pdf-lib and pdfjs-dist.

How the privacy claim works

Each tool downloads its required code into your browser when you first open it. Then it processes your file using JavaScript, WebAssembly, or WebGPU — running on your laptop's CPU and GPU, in your browser tab's sandboxed memory. The file is read into memory, processed, and offered to you as a download. At no point is it transmitted to a server.

You can verify this for any tool:

  1. Open the tool (for example, Video Compressor).
  2. Open browser DevTools (F12 or right-click → Inspect).
  3. Switch to the Network tab and click the trash-can icon to clear past requests.
  4. Drop a file into the tool.
  5. You'll see network activity only for code loading from www.toolkoala.com or, for FFmpeg-based tools, from unpkg.com. You will not see a request body containing your file's bytes.

This is the kind of privacy claim that doesn't depend on trusting us. If we changed the code tomorrow to start uploading files, you would see it in DevTools immediately.

How this is funded

Right now: nothing. I cover hosting out of pocket. The project is small enough that this is sustainable for a while.

The plan is to apply for Google AdSense — if approved, ToolKoala will show ads in fixed slots on tool pages and the blog. These ads don't depend on your file contents (they can't; the files never leave your browser). Ad targeting uses only standard browser-level signals: rough location, device type, and the tool you're on. If you run an ad blocker, the tools still work normally.

If AdSense doesn't approve — which happens — I'll switch to referral / affiliate sponsorships from products I personally use and trust. No "sponsored tool" payments, no premium tier, no email collection. Same product for everyone.

What we're working on

Recent additions: Video to GIF conversion, MP3 audio compression, and browser-based OCR. Upcoming areas of focus: improving multilingual coverage (currently most tool descriptions are auto-translated; we're replacing them with native-speaker content), reducing the initial bundle size for better mobile performance, and expanding the blog with deeper technical write-ups about how each tool works under the hood.

If there's a tool you wish existed, or one of mine is broken on your specific file format, email me. I read every message.

Who's behind it

Just me. ToolKoala is a one-person independent project — no VC backing, not a side project of a larger company, no salespeople, no fundraising. Every engineering and product decision is made by someone who actually uses the tools: me. If you send feedback, it reaches a human — me — usually within a few hours, not a routing queue. I never auto-reply with AI; even a three-line answer is typed by hand.

I build this in my spare time, but I hold it to a full-time standard: every tool has to work, every translation has to read naturally to a native speaker, and every bug report has to be seen by a person.

Stay updated

Read about the technical and product choices on our blog. We write occasional deep-dives on browser-based tooling, real-world tool comparisons, and engineering trade-offs we've made along the way. No newsletter; no email collection.

— Milo 🐨 · [email protected]